1. Field of the Invention
The present invention relates to cartridges for sealingly connecting fluid devices to a pressure vessel and, more particularly, to a quick connection cartridge for connecting vehicle brake lines, fittings and valves to an air reservoir tank.
2. Description of the Prior Art
Air reservoir tanks are commonly used in vehicles to supply air to air-pressure operated components. For example, trucks or semi-trailers often utilize flexible pneumatic air lines to deliver air under pressure for braking functions and for operating auxiliary pneumatic devices. Reliable transmission of air pressure and the connection of pneumatic air lines to an air reservoir tank can be problematic.
Commonly, fittings on air reservoir tanks have been made by punching or forming a hole in the wall of the tank and welding a threaded bushing at the hole, having internal NPT-type pipe threads. The connector or device to be mounted or supported has corresponding external NPT interference-fit threads connected to communicate with the tank interior. Such arrangements have led to persistent leakage problems since NPT-type threads do not reliably hold air pressure, particularly where the working pressures may run as high as 150 psi. Such leakage problems have resulted in the need for the application of sealants to the threads resulting in additional expense and assembly time.
Additionally, traditional threaded connections necessarily result in the deformation of the threads of the bushing and connector or device. Such deformation aggravates the leakage problem particularly when the connector or device is interchanged with a different connector or device. Additionally, since the angular orientation of the connector or device mounted within the bushing determines the interference and resulting seal between the threads, reorientation of the connector or device is usually not possible. Traditional threaded connections therefore provide little flexibility in positioning of the connector or device supported by the bushing.
In recognition of the above noted problems with conventional threaded connections, quick connect cartridges have been proposed as a substitute therefor. Such quick connect cartridges typically include outer brass rings or fingers which create a mechanical interference between the cartridge and the receiving bushing. However, these quick connect cartridges often suffer from the drawback of being difficult to insert within the bushing resulting in increased assembly time and expense. Additionally, traditional quick connect cartridges are often deformed after prolonged use, thereby preventing their interchangeable reuse within various bushings. Finally, connection cartridges are required to have very high pull-off forces, particularly in the application of connecting brake lines to an air reservoir tank in a vehicle. Because traditional quick connect cartridges typically lack the required high pull-off forces, they are often unacceptable for connecting such brake lines.
Accordingly, there is a need for a connection cartridge for sealingly connecting fluid devices to an air tank which eliminates threaded connections and, at the same time, is easily replaceable while permitting angular reorientation of the device connected thereto.
The connection cartridge for air tanks, according to the present invention, is designed to be used in metal tanks, such as steel or aluminum, or may also be used on composite-wound air tanks, such as for heavy duty air systems for truck air brakes and the like. The common maximum working pressure for such reservoirs is 150 pounds per square inch gauge (psig). The connection cartridge of this invention is designed to receive a multitude of fluid devices. More particularly, the cartridge may be used as both a housing for coupling devices for connecting air lines, and as a housing for valves which are typically found in truck air brake reservoirs, including one way check valves, pressure protection valves, drain valves, pressure relief valves, and the like.
The cartridge of the present invention is sealingly received within a bushing fixed to a domed end wall of an air reservoir tank. The bushing includes a cylindrical body having a receiving bore extending between opposing proximal and distal ends. An annular retaining groove is provided proximate the distal end of the cylindrical body while an annular bearing surface is positioned between the retaining groove and the proximal end.
A cartridge is slidably and concentrically received within the receiving bore of the bushing and includes a passageway extending between opposing inlet and outlet ends. An engagement shoulder is positioned proximate the outlet end for engaging the annular bearing surface of the bushing, thereby preventing axial movement of the cartridge inwardly in a proximal direction toward the interior of the air reservoir tank. An annular O-ring receiving recess is positioned between the engagement shoulder and the inlet end of the cartridge. An O-ring is received within the annular O-ring receiving recess for providing sealing engagement between the bushing and the cartridge. A snap ring is received within the annular retaining groove of the bushing and is engagable with a distally facing retaining surface of the cartridge, thereby preventing movement of the cartridge outwardly in a distal direction away from the interior of the air reservoir tank.
The passageway of the cartridge is adapted to sealingly receive a fluid device. Such fluid devices may comprise push-to-connect fittings, check valves, pressure relief valves, and the like.
It is accordingly an object of the present invention to provide a connection cartridge for receiving a fitting or valve for communicating with an air reservoir tank of an air brake system which eliminates threaded connections between the cartridge and the tank.
A further object of the present invention is to provide such a cartridge which substantially eliminates leakage between the air reservoir tank and the fitting or valve.
Another object of the present invention is to provide a cartridge which is easily installed thereby reducing assembly time.
It is a further object of the present invention to provide such a cartridge which eliminates the need for sealants.
It is yet another object of the present invention to provide such a cartridge for receiving a push-to-connect fitting which permits communication between the air reservoir tank and brake lines, and which further permits the free rotation of the fitting and brake line relative to the tank.
A further object of the invention is to provide a cartridge received within an air reservoir tank which is easily serviceable and replaceable.